A5045986094- Galaxies: Formation, Evolution, Phenomena
- Cosmology and Gravitation Theories
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Radio Astronomy Observations and Technology
- Gamma-ray bursts and supernovae
- Dark Matter and Cosmic Phenomena
- Astrophysics and Cosmic Phenomena
- Scientific Research and Discoveries
- Adaptive optics and wavefront sensing
- Geophysics and Gravity Measurements
- History and Developments in Astronomy
- Statistical and numerical algorithms
- Astronomical Observations and Instrumentation
- Computational Physics and Python Applications
- Pulsars and Gravitational Waves Research
- Calibration and Measurement Techniques
- Solar and Space Plasma Dynamics
- Astrophysical Phenomena and Observations
- Advanced Thermodynamics and Statistical Mechanics
- Neutrino Physics Research
- Advanced X-ray Imaging Techniques
- Data Visualization and Analytics
- Blind Source Separation Techniques
- Various Chemistry Research Topics
Queen Mary University of London
2024-2025
University of the Western Cape
2021-2025
University College London
2024
University of Copenhagen
2024
Flatiron Health (United States)
2024
Flatiron Institute
2024
Royal Holloway University of London
2024
University of California, Davis
2024
New York University
2024
Princeton University
2024
We forecast constraints on primordial non-Gaussianity (PNG) and bias parameters from measurements of galaxy power spectrum bispectrum in future radio continuum optical surveys. In the bispectrum, we consider a comprehensive list effects, including expansion for non-Gaussian initial conditions up to second order, redshift space distortions, uncertainties theoretical errors. These effects are all combined single PNG first time. Moreover, improve modelling over previous forecasts, by accounting...
The Hydrogen Intensity and Real-time Analysis eXperiment (HIRAX) is a radio interferometer array currently in development, with an initial 256-element to be deployed at the South African Radio Astronomy Observatory (SARAO) Square Kilometer Array (SKA) site Africa. Each of 6m, $f/0.23$ dishes will instrumented dual-polarisation feeds operating over frequency range 400-800 MHz. Through intensity mapping 21 cm emission line neutral hydrogen, HIRAX provide cosmological survey distribution...
Primordial non-Gaussianity (PNG) is one of the most powerful probes early Universe and measurements large scale structure have potential to transform our understanding this area. However relating late time primordial perturbations challenging due non-linear processes that govern evolution Universe. To help address issue we release a suite N-body simulations containing four types PNG: \textsc{quijote-png}. These were designed augment \textsc{quijote} explored impact various cosmological...
Abstract We investigate how much can be learnt about four types of primordial non-Gaussianity (PNG) from small-scale measurements the halo field. Using quijote-png simulations, we quantify information content accessible with power spectrum monopole and quadrupole, matter spectrum, halo–matter cross bispectrum monopole. This analysis is first to include small, nonlinear scales, up <?CDATA ${k}_{\max }=0.5\,{\rm{h}}\,{\mathrm{Mpc}}^{-1}$?> <mml:math...
Abstract The power spectrum and bispectrum of dark matter tracers are key complementary probes the Universe. Next-generation surveys will deliver good measurements bispectrum, opening door to improved cosmological constraints breaking parameter degeneracies, from combination bispectrum. Multi-tracer spectra have been used suppress cosmic variance mitigate effects nuisance parameters systematics. We present a multi-tracer formalism that can be applied next-generation survey data. Then we...
This white paper envisions a revolutionary post-DESI, post-LSST dark energy program based on intensity mapping of the redshifted 21cm emission line from neutral hydrogen at radio frequencies. The proposed survey has unique capability to quadruple volume Universe surveyed by optical programs, provide percent-level measurement expansion history $z \sim 6$, open window explore physics beyond concordance $Λ$CDM model, and significantly improve precision standard cosmological parameters. In...
Primordial features, in particular oscillatory signals, imprinted the primordial power spectrum of density perturbations represent a clear window opportunity for detecting new physics at high-energy scales. Future spectroscopic and photometric measurements from $Euclid$ space mission will provide unique constraints on spectrum, thanks to redshift coverage high-accuracy measurement nonlinear scales, thus allowing us investigate deviations standard power-law spectrum. We consider two models...
Abstract Primordial non-Gaussianity of the local type induces a strong scale-dependent bias on clustering halos in late-time Universe. This signature is particularly promising to provide constraints parameter f NL from galaxy surveys, as amplitude grows with scale and becomes important large, linear scales. However, there well-known degeneracy between real prize, parameter, (non-Gaussian) assembly i.e., halo formation history-dependent contribution signal, which could seriously compromise...
Clustering measurements of Gravitational Wave (GW) mergers in Luminosity Distance Space can be used the future as a powerful tool for Cosmology. We consider tomographic Angular Power Spectrum both an Einstein Telescope-like detector network and some more advanced scenarios (more sources, better distance measurements, sky localization). produce Fisher forecasts cosmological (matter dark energy) merger bias parameters. Our fiducial model number distribution GW events is based on results from...
Future Large Scale Structure surveys are expected to improve over current bounds on primordial non-Gaussianity (PNG), with a significant impact our understanding of early Universe physics. The level such improvements will however strongly depend the extent which late time non-linearities erase PNG signal small scales. In this work, we show how much information remains in bispectrum non-linear dark matter density field by implementing new, simulation-based, methodology for joint estimation...
Abstract We study the clustering of Gravitational Wave (GW) merger events and Supernovae IA (SN), as cosmic tracers in Luminosity Distance Space. modify publicly available CAMB code to numerically evaluate auto- cross- power spectra for different sources, including Space distortion effects generated by peculiar velocities lensing convergence. perform a multitracer Fisher analysis forecast expected constraints on cosmological GW bias coefficients, using outputs from hydrodynamical N-body...
Abstract We study signatures of primordial non-Gaussianity (PNG) in the redshift-space halo field on nonlinear scales using a combination three summary statistics, namely, mass function (HMF), power spectrum, and bispectrum. The choice adding HMF to our previous joint analysis spectrum bispectrum is driven by preliminary field-level analysis, which we train graph neural networks catalogs infer PNG f NL parameter. covariance matrix responses summaries changes model parameters are extracted...
The 21cm emission of neutral hydrogen is a potential probe the matter distribution in Universe after reionisation. Cosmological surveys this line intensity will be conducted coming years by SKAO and HIRAX experiments, complementary to upcoming galaxy surveys. We present first forecasts cosmological constraints from combination power spectrum bispectrum. Fisher are computed for constraining these on parameters, BAO distance functions growth function. also estimate dynamical dark energy...
We analyse the clustering of 22,361 quasars between redshift 2.2 < z 2.9 observed with Sloan Digital Sky Survey (SDSS)-III Baryon Oscillation Spectroscopic (BOSS), which are included in ninth data release (DR9). fit results a {\Lambda}CDM model to calculate linear bias quasar sample, b=3.74\pm 0.12. The measured value is consistent findings White et al. (2012), where they almost same although only range, s<40 Mpc/h. At large scales we observe an excess or plateau correlation function. By...
We forecast the ability of dedicated 21 cm intensity mapping experiments to constraint primordial non-Gaussianity using power spectrum and bispectrum. model signal by including non-linear biasing expansion through a generalized halo approach. consider importance foreground filtering scale wedge. find that current generation like CHIME do not posses sufficient sensitivity be competitive with existing limits. On other hand, upcoming HIRAX can improve constraints proposed PUMA experiment...
We explore the information content of 21 cm intensity maps in redshift space using 1-loop Effective Field Theory power spectrum model and bispectrum at tree level. The signal contains signatures dark matter, energy growth large-scale structure Universe. These are typically analyzed via 2-point correlation function or spectrum. However, adding from 3-point will be crucial to exploiting next-generation mapping experiments. could offer a unique opportunity break key parameter degeneracies that...
MegaMapper is a proposed ground-based experiment to measure Inflation parameters and Dark Energy from galaxy redshifts at 2<z<5. A 6.5-m Magellan telescope will be coupled with DESI spectrographs achieve multiplexing of 20,000. would located Las Campanas Observatory fully access LSST imaging for target selection.
The expansion of the Universe is understood to have accelerated during two epochs: in its very first moments a period Inflation and much more recently, at $z < 1$, when Dark Energy hypothesized drive cosmic acceleration. undiscovered mechanisms behind these epochs represent some most important open problems fundamental physics. large cosmological volume $2 z 5$, together with ability efficiently target high-$z$ galaxies known techniques, enables gains study Energy. A future spectroscopic...
Abstract We study primordial non-Gaussian signatures in the redshift-space halo field on nonlinear scales, using a quasi-maximum likelihood estimator based optimally compressed power spectrum and modal bispectrum statistics. train validate suite of catalogs constructed from Quijote-png N -body simulations, which we release to accompany this paper. verify its unbiasedness near-optimality for three main types non-Gaussianity (PNG): local, equilateral, orthogonal. compare expansion with k...
Abstract We present the results of a set cosmological N-body simulations with standard ΛCDM cosmology but characterized by scale-dependent primordial non-Gaussianity local type featuring power-law dependence f NL loc ( k ) at large scales followed saturation to constant value smaller where non-linear growth leads formation collapsed cosmic structures. Such models are built ensure consistency current Cosmic Microwave Background bounds on yet allowing for effects non-Gaussian statistics...
The power spectrum and bispectrum of dark matter tracers are key complementary probes the Universe. Next-generation surveys will deliver good measurements bispectrum, opening door to improved cosmological constraints breaking parameter degeneracies, from combination bispectrum. Multi-tracer spectra have been used suppress cosmic variance mitigate effects nuisance parameters systematics. We present a multi-tracer formalism that can be applied next-generation survey data. Then we perform...